build: enable vendor experiment for go1.5
build: enable vendor experiment for go1.5

a-robinson/etcd,ravigadde/etcd,dnaeon/etcd,xiang90/etcd,nekto0n/etcd,qqsun8819/etcd,CrazyJvm/etcd,glevand/coreos--etcd,visheshnp/etcd,lorneli/etcd,jlamillan/etcd,fanminshi/etcd,li-ang/etcd,whuwxl/etcd,sofuture/etcd,luxas/etcd,zaphod-concur/etcd,etcd-io/etcd,gyuho/etcd,armstrongli/etcd,akauppi/etcd,qqsun8819/etcd,westhood/etcd,linuxcer/etcd,fanminshi/etcd,nekto0n/etcd,armstrongli/etcd,whuwxl/etcd,sofuture/etcd,sinsharat/etcd,coreos/etcd,linuxcer/etcd,dannysauer/etcd,joshix/etcd,glycerine/etcd,bluebreezecf/etcd,purpleidea/etcd,yudai/etcd,wantonsolutions/dinv-etcd,ajityagaty/etcd,coreos/etcd,tamird/etcd,mkumatag/etcd,ktateish/etcd,vimalk78/etcd,swingbach/etcd,gyuho/etcd,etcd-io/etcd,dnaeon/etcd,StorReduce/etcd,hongchaodeng/etcd,li-ang/etcd,akauppi/etcd,lorneli/etcd,tguangch/etcd,rnaveiras/etcd,sinsharat/etcd,OyTao/etcd_learning,joshix/etcd,plasticbox/etcd,chipironcin/etcd,achanda/etcd,cockroachdb/etcd,hongchaodeng/etcd,heyitsanthony/etcd,mkumatag/etcd,westhood/etcd,a-robinson/etcd,mqliang/etcd,dannysauer/etcd,mickep76/etcd,swingbach/etcd,ktateish/etcd,rchicoli/etcd,glevand/coreos--etcd,StorReduce/etcd,bluebreezecf/etcd,handsomesun/etcd,luxas/etcd,jonboulle/etcd,OyTao/etcd_learning,tguangch/etcd,rnaveiras/etcd,bdarnell/etcd,insequent/etcd,handsomesun/etcd,achanda/etcd,insequent/etcd,mqliang/etcd,ajityagaty/etcd,purpleidea/etcd,YuleiXiao/etcd,mickep76/etcd,wantonsolutions/dinv-etcd,zaphod-concur/etcd,endocode/etcd,tamird/etcd,rchicoli/etcd,cockroachdb/etcd,etcd-io/etcd,chipironcin/etcd,jonboulle/etcd,jlamillan/etcd,xiang90/etcd,YuleiXiao/etcd,lumjjb/etcd,lumjjb/etcd,CrazyJvm/etcd,wantonsolutions/dinv-etcd,vimalk78/etcd,rnaveiras/etcd,glycerine/etcd,sebrandon1/etcd,endocode/etcd,ajityagaty/etcd,bdarnell/etcd,visheshnp/etcd,mkumatag/etcd,sebrandon1/etcd,mqliang/etcd,heyitsanthony/etcd,plasticbox/etcd,yudai/etcd,ravigadde/etcd